1. Field of the Invention
The invention relates to a method for phase matching, and more particularly, to a method for phase matching between a first element and a second element by detecting a magnetic flux.
2. Description of the Prior Art
In industry, many electronic products or mechanical products contain some devices or elements that need to be fine-tuned under different situations and applications in order to optimize the performance of the product. In actual applications of fine-tuning, screws are usually chosen as a preferred medium. This is because screws have the advantages of simplicity of structure and low cost. And most importantly, a screw has the characteristic of transferring a rotational phase variation along a vertical axis of its body into a positional variation along the vertical axis with respect to an object where the screw is installed. By designing the distance between threads (or pitch) of a screw, the ratio of the phase variation with respect to the positional variation can be set as a large value, which means, when the screw rotates along a vertical axis of its body with a large phase variation, the relative positional variation will have a rather small quantity. If the phase variation is used as a fine-tuning mechanism (for example, by rotating the screw with a screwdriver), and the positional variation is related to a status variation of a device or an element of mechanical or electrical design that needs to be tuned (for example, a vertical displacement of a rod, or a resistance of a variable resistor), a very precise fine-tuning process can be achieved through the above setting. According to the characteristics of screws mentioned above, screws are quite suitable for fine-tuning applications.
The relationship between a screw and a screwdriver used for rotating the screw is described as follows. The screw will receive a torque along an axis given by the screwdriver to perform the phase variation, and this usually depends on the geometrical shape of a recess of the screw being matched with the geometrical shape of a screw bit of the screwdriver. Due to the nature of the recess of an ordinary screw (usually a cross-shaped recess or a slotted recess), before the screwdriver can have a perfect match with the screw and start to actually give a torque to the screw and successfully change its phase, the screwdriver has to rotate with an angle such that the relative position of the bit and the recess match. But, since the relative positions of screws and the screwdriver before every matching process are different, the angle rotated has an unpredictable value. This situation causes great trouble for an assembly line executed fine-tuning process with an automatic controlling program. In an assembly line procedure when a device is set to be fine-tuned to a certain degree, and the fine-tuning process is implemented through a certain phase variation of a screw in the device made by a screwdriver, the above-mentioned unpredictability of the angle then becomes an error factor of the fine-tuning process. The automatic controlling program is not able to determine the angle deviation and cannot compensate for it with the rotation of the screwdriver, causing error in the actual tuning result from the expected tuning degree. This error is usually, for a fine-tuning process, unacceptable. According to the prior art, in order to alleviate problems caused by this fine-tuning error, screws having more slots in their recesses (for example, six slots or more) are usually used for reducing the unpredictable angle so as to reduce the error. Alternatively, screws with a sophisticated recess structure along with corresponding screwdrivers are designed to perform a series of mechanical matching procedures that can insure the transfer of the torque on the screw from the very beginning of the rotation of the screwdriver.
However, screws having more slots in their recesses or screws with sophisticated recess structures are not easily obtained. Additional custom-made assembly lines are needed and the manufacturing processes are more complicated than ordinary screws, so costs of these screws are high. Additionally, screws having more slots in their recesses do not even fully eliminate the error but rather reduce it to an acceptable range. They are not the ideal fine-tuning tools for mass production assembly lines.